The complaint filed with the European Comission was made by 23 consumer groups from 19 countries, who claimed the airlines have made misleading climate-related claims that breached EU commercial rules, the European Consumer Organization (BEUC) has said.
The airlines involved in the suit are Air Baltic, Air Dolomiti, Air France, Austrian, Brussels Airlines, Eurowings, Finnair, KLM, Lufthansa, Norwegian, Ryanair, SAS, SWISS, TAP, Volotea, Vueling, Wizz Air.
Aviation, which accounts for approximately 3 per cent of total CO2 emissions worldwide, is considered a hard-to-abate sector due to a lack of technologically mature alternatives to traditional jet-fuelled engines. Currently, decarbonisation efforts are focused on lowering the carbon emissions of jet fuel by mixing conventional fuel with sustainable aviation fuel (SAF) and carbon offsetting and reduction schemes.
However, decarbonising the sector is still an ongoing process. BEUC and its partners have criticised the airlines for "giving consumers the impression that flying is sustainable".
"This is simply untrue as flying is not sustainable and is not bound to become so in the near future," BEUC said in a press release. "Where airlines have proposed consumers to pay extra 'green' fees based on such misleading claims, CPC authorities should request airlines to reimburse their customers."
BEUC members have taken issue with several practices made by the airlines. These include claiming that extra credits can "offset", "neutralise", or "compensate" the CO2 emissions, charging customers extra to contribute to the development of 'Sustainable Aviation Fuels' (SAFs) and implying that air travel can be done in an environmentally-responsible way.
According to BEUC, the notion that consumers can "neutralise" the impact of their flight through climate offsetting schemes is "factually incorrect".
"The climate benefits of offsetting activities are highly uncertain, while the harm caused by the CO2 emissions from air travel is certain," BEUC said in a statement.
They have called for a Europe-wide investigation into the issue and for airlines to put a stop to these practices.
"We urge authorities to take the matter into their hands and crack down on this greenwashing practice seriously misleading consumers," said Ursula Pachl, BEUC's Deputy Director General of BEUC.
"Whether you pay a 'green fare' or not, your flight will still emit climate-harmful gases. Technological solutions to decarbonise aviation won't become a massive-scale reality any time soon, so depicting flying as a sustainable mode of transport is pure greenwashing. At a time when many want to travel more sustainably, airlines should urgently stop offering consumers a fake peace of mind."
An Air France-KLM spokesman said the Franco-Dutch group was "paying increased attention to the precision of these messages" and that it was the world's biggest buyer of sustainable aviation fuels last year.
Germany's Lufthansa said it plans to slash its net emissions by half by 2030 compared to 2019 levels and has a "constant dialogue" with customers.
In October, the 193 countries that form the International Civil Aviation Organisation (ICAO), pledged to support an "aspirational" goal that would see the sector achieve net zero carbon emissions by 2050.
However, a survey conducted by GE Aerospace found the majority of aviation experts are not convinced that the sector will become carbon neutral by the stated 2050 goal. Out of 325 aviation decision-makers from companies across the world, only 46 per cent said they believed the industry will meet its net-zero goal by 2050. Meanwhile, 32 per cent said it will not and 22 per cent were unsure.
